In general, television (TV) sets, beam projectors, air conditioners, air cleaners, etc. used in homes are controlled by infrared remote controllers. Since such devices used in a home individually have their own remote controllers, several remote controllers are required to control the devices. However, such remote controllers have many disadvantages. For example, the remote controllers are frequently lost, and their batteries are required to be frequently replaced with new ones.
Therefore, home network systems have been developed as ubiquitous environments. However, products, which have been developed before the home network systems are commonly used, are not controlled by the home network systems.
Also, although devices, which have been developed before home network systems are commonly used, are controlled using an infrared signal controlling apparatus, a problem may occur due to the linearity of an infrared signal or an obstacle may be positioned in the middle of the infrared signal. If the devices are too distant from the infrared signal controlling apparatus for the infrared signal to reach the devices, the devices may not be conveniently controlled by the infrared signal.